Normally, a frame for a motor vehicle is made up of a central body, which constitutes the passenger compartment, a front body, which supports the front wheels, and a rear body, which supports the rear wheels. The engine can be set in a front position, and hence be housed in the front body, or else in a central or rear position, and hence be housed in the rear body.
The frame can be monolithic, i.e., there is no discontinuity between the front body, the central body, and the rear body, or else can be dismantleable, i.e., the front body and/or the rear body are/is bolted to the central body and hence can be separated from the central body itself. A frame that can be dismantled is chosen so as to render both the operations of initial assembly of the vehicle and the operations of repair of the vehicle in the event of accidents simpler and of lower cost.
In a known frame that can be dismantled, the central body has a front connection bar and a rear connection bar, which are set in a transverse direction (i.e., in a direction perpendicular to the longitudinal axis of the automobile) and a set of longitudinal bars (i.e., parallel to the longitudinal axis of the automobile) is provided, each equipped with a first flange. Bolted to each first flange is a corresponding second flange of a longitudinal bar of the front body or of the rear body for rigid connection of the front body or of the rear body to the central body.
A known frame of the type as the one described above is heavy and complex to build, in so far as it is necessary to provide a large number of flanges, and is complicated to assemble, in so far as the bolts that connect two facing flanges must be inserted longitudinally (i.e., parallel to the longitudinal axis of the automobile) in an area that is difficult to access longitudinally.
FR2618746 discloses a removable motor vehicle structure and a method for assembling a vehicle including such a structure.
WO9932346 discloses a chassis for a passenger car, comprising a dimensionally stable central cell formed by longitudinal beams and cross beams, a front wagon connected thereto and a rear wagon connected to the former, each of which comprise at least one wheel axle, a front-wheel axle assembly or a back-wheel.